1. Field of the Invention
The present invention relates to a liquid crystal display device comprising a liquid crystal injection port sealed with a sealant.
2. Description of the Related Art
For example, a TFT (Thin Film Transistor) active matrix driving type of liquid crystal display device comprises two opposed substrates including a substrate (referred to as a "TFT substrate" hereinafter) on which TFTs are formed, and a substrate (referred to as a "counter substrate" hereinafter) on which a whole-surface counter electrode is formed, and a liquid crystal sealed between the two substrates. Each of the pixel electrode on the TFT substrate and the whole-surface counter electrode on the counter substrate is a transparent electrode comprising, for example, indium oxide mixed with tin oxide (Indium Tin Oxide; referred to as "ITO" hereinafter). The process for manufacturing such a liquid crystal display device, for example, comprises printing a sealant to laminate the two substrates with leaving a liquid crystal injection port in the periphery of one of the two substrates, injecting a liquid crystal between the two substrates through the liquid crystal injection port, and sealing the substrates with a sealant, for example, comprising an ultraviolet curable resin.
The conventional process for manufacturing a liquid crystal display device causes peeling between a sealant and the surface of a substrate due to thermal stress in ultraviolet irradiation of the sealant with which the liquid crystal injection port is filled and which comprises an ultraviolet curable resin, for curing the sealant, thereby causing the problem of deteriorating moisture resistance of the sealing portion (liquid crystal injection port) of the liquid crystal display device. As a measure against this problem, ITO for a transparent electrode is disposed over the whole surface of a part of the surface of a substrate which contacts the sealant. However, in this case, although there is no problem with the adhesion between the sealant and the ITO on the surface of the substrate, ITO is cracked due to thermal stress in ultraviolet irradiation for curing the sealant, thereby causing the problem of deteriorating moisture resistance of the sealing portion of the liquid crystal display device.